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107:. They are characteristic of mountain glaciation in particular. They have a characteristic U shape in cross-section, with steep, straight sides and a flat or rounded bottom (by contrast, valleys carved by rivers tend to be V-shaped in cross-section). Glaciated valleys are formed when a glacier travels across and down a slope, carving the valley by the action of scouring. When the ice recedes or thaws, the valley remains, often littered with small boulders that were transported within the ice, called
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to be carved into a U-shaped valley. These valleys can be several thousand feet deep and tens of miles long. Glaciers will spread out evenly in open areas, but tend to carve deep into the ground when confined to a valley. Ice thickness is a major contributing factor to valley depth and carving rates.
261:, and over-deepenings anywhere from ten to hundreds of meters deep. These then fill in with sediments to create plains or water to create lakes, sometimes referred to as "string-of-pearl" or ribbon lakes. Such water filled U-valley basins are also known as "fjord-lakes" or "valley-lakes" (Norwegian:
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The floors of these glacial valleys are where the most evidence can be found regarding glaciation cycles. For the most part, the valley floor is wide and flat, but there are various glacial features that signify periods of ice transgression and regression. The valley can have various steps, known as
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Geologists did not always believe that glaciers were responsible for U-shaped valleys and other glacial erosional features. Ice is quite soft and it was unbelievable to many that it could be responsible for the severe carving of bedrock characteristic of glacial erosion. German geologist Penck and
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After deglaciation, snow and ice melt from the mountain tops can create streams and rivers in U-shaped valleys. These are referred to as misfit streams. The streams that form in hanging valleys create waterfalls that flow into the main valley branch. Glacial valleys may also have natural, often
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shape is caused by glacial erosion removing the contact surfaces with greatest resistance to flow, and the resulting section minimises friction. There are two main variations of this U-shape. The first is called the Rocky
Mountain model and it is attributed to alpine glacial valleys, showing an
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Progress was made in the 1970s and 1980s on the possible mechanisms of glacial erosion and U-shaped valleys via models proposed by various scientists. Numerical models have been created to explain the phenomenon of carving U-shaped valleys.
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As a glacier moves downhill through a valley, usually with a stream running through it, the shape of the valley is transformed. As the ice melts and retreats, the valley is left with very steep sides and a wide, flat floor. This
289:(514 m). The longitudinal profile of a U-shaped, glaciated valley is often stepwise where flat basins are interrupted by thresholds. Rivers often dig a V-shaped valley or gorge through the threshold.
201:, from the Norwegian word for these features that are common in Norway. Outside of Norway, a classic U-shaped valley that is also a fjord is the Western Brook Pond Fjord in
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331:. They are believed to have been formed where a number of small glaciers merge to produce a much larger glacier. Examples include: Warnscale Bottom in the
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411:. These geomorphic features significantly influence sediment distribution and biological communities through their modification of current patterns.
72:, NW Indian Himalaya. The glacier visible at the head of the valley is the last remnant of the formerly much more extensive glacier which carved it.
701:"Geomorphologic and Glacial Evolution of the Cachapoal and southern Maipo catchments in the Andean Principal Cordillera, Central Chile (34°-35º S)"
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overall deepening effect on the valley. The second variation is referred to as the
Patagonia-Antarctica model, attributed to continental
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Surrounding smaller tributary valleys will often join the main valleys during glaciation periods, leaving behind features known as
780:, et al. (2012). "51 – Banks, Troughs, and Canyons on the Continental Margin off Lofoten, Vesterålen, and Troms, Norway".
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Valley head or trough end at
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known as the 'trough end' or 'trough head'. This may have almost sheer rock walls and spectacular
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Examples of U-shaped valleys are found in mountainous regions throughout the world including the
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304:. They are created due to excess sediment and glacial till moved and deposited by the glacier.
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When a U-shaped valley extends into saltwater, becoming an inlet of the sea, it is called a
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Waddington, E. D.; Anderson, S. P.; Anderson, R. S.; MacGregor, K. R. (November 2000).
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American geologist Davis were vocal supporters of this unprecedented glacial erosion.
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Hamblin, P. F., & Carmack, E. C. (1978). River‐induced currents in a Fjord Lake.
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Glacial troughs also exist as submarine valleys on continental shelves, such as the
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699:; Iturrizaga, Lafasam; Charretier, Sebastién; Regard, Vincent (2019).
523:. Department of Geography, Central Michigan University. Archived from
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A glacial trough or glaciated mountain valley often ends in an abrupt
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valley in Norway ends abruptly giving rise to tall waterfalls.
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and displaying an overall widening effect on its surroundings.
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281:-lakes. Some of these fjord-lakes are very deep for instance
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of the Andes, glacial valley floors may be covered by thick
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10.1130/0091-7613(2000)28<1031:NSOGLP>2.0.CO;2
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Pages displaying short descriptions of redirect targets
451: – Valley in the upper third of a mountain range
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436: – Landform created by the action of glaciers
469: – Valley with a tributary to a larger river
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642:Delta: naturgeografi for den videregående skolen
521:Illustrated Glossary of Alpine Glacial Landforms
457: – Glacially formed accumulation of debriss
182:runs. Another well-known U-shaped valley is the
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385:road climbs the steep cliffs of the trough end.
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296:high in the trough walls after the ice melts.
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230:Formation of a U-shaped valley happens over
782:Seafloor Geomorphology as Benthic Habitat
767:, London: AldineTransaction, 1970, p.359.
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307:In volcanic mountain ranges, such as the
300:dam-like, structures within them, called
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663:Journal of Geophysical Research: Oceans
493:"glacial valley | geological formation"
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38:showing the characteristic U shape.
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27:Valleys formed by glacial scouring
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749:Blackie's Dictionary of Geography
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170:. A classic glacial trough is in
751:, Mumbai: Blackie, 2000, p. 344.
517:"Glacial Trough/U-Shaped Valley"
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277:lakes in Norway are examples of
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103:, are formed by the process of
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815:Key Concepts in Geomorphology
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80:U-shaped valley with lake in
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88:, Sogn og Fjordane, Norway.
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678:. Oslo: Universitetsforl.
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34:A glaciated valley in the
840:Glacial erosion landforms
720:10.5027/andgeoV46n2-3108
640:Karlsen, Ole G. (1981).
597:"Wiley Online Library".
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221:Glacier Valley formation
203:Gros Morne National Park
765:Dictionary of Geography
674:Gjessing, Just (1978).
497:Encyclopedia Britannica
622:Cite journal requires
607:10.1002/esp.3290130805
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144:Scandinavian Mountains
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813:Bierman; et al.
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172:Glacier National Park
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784:. pp. 703–715.
527:on 27 September 2020
309:Principal Cordillera
148:Carpathian Mountains
178:, USA in which the
64:U-shaped valley in
697:Charrier, Reynaldo
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409:Laurentian Channel
370:The deep U-shaped
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168:Scottish Highlands
128:Caucasus Mountains
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799:978-0-12-385140-6
763:Monkhouse, F.J.,
676:Norges landformer
567:(11): 1031–1034.
561:Geology (Boulder)
434:Glacial landforms
285:(453 meters) and
49:U-shaped valley,
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467:Side valley
461:Ribbon Lake
449:High valley
383:Trollstigen
375: [
356:Switzerland
354:valleys in
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140:New Zealand
845:Glaciology
829:Categories
684:8200017729
650:8251814782
502:2017-05-23
474:References
372:Isterdalen
339:, and the
329:waterfalls
319:Trough end
313:lava flows
246:ice sheets
209:, Canada.
186:valley in
166:, and the
105:glaciation
53:Mountain,
47:Malyovitsa
747:Blackie,
581:0091-7613
556:"Geology"
345:Engstlige
241:parabolic
213:Formation
188:Snowdonia
86:Nordfjord
531:8 August
428:See also
302:moraines
263:fjordsjø
164:Bulgaria
152:Pyrenees
142:and the
132:Himalaya
68:valley,
55:Bulgaria
850:Valleys
726:June 9,
455:Moraine
415:History
176:Montana
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275:Bandak
271:Gjende
267:dalsjø
154:, the
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283:Mjøsa
279:fjord
226:Shape
199:fjord
192:Wales
160:Pirin
120:Andes
794:ISBN
728:2019
680:ISBN
646:ISBN
628:help
577:ISSN
533:2019
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